How do you calculate the formal charge of O3?

1 Answer
Nov 7, 2015

Answer:

The formal charge of the ozone molecule is zero. Its Lewis structures do present charge separation.

Explanation:

With simple VSEPR considerations, there are 18 valence electrons to distribute around the 3 oxygen atoms (24 electrons in total; 6 are inner core).

Typically, a Lewis structure of #O=stackrel(ddot)O^(+)-O^(-)#, would be depicted. Going from left #O# to right #O# and including the 2 inner core electrons on each atom, there are 8, 7, and 9 electrons around each oxygen centre, resulting in formal charges of #0#, #+1#, and #-1#, respectively. Of course, I can draw the other resonance structure, but the Lewis structure has the same electronic formulation. The #/_O-O-O# #~=117^@#; this is slightly LESS than the normal #sp_2# bond angle of #120^@#, due to disproportionate influence of the oxygen lone pair, which tends to compress #/_O-O-O#.

Since the central oxygen has 3 regions of electron density, this molecule is bent.